/**************************************************************************** * net/icmpv6/icmpv6_neighbor.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include "netdev/netdev.h" #include "devif/devif.h" #include "inet/inet.h" #include "neighbor/neighbor.h" #include "route/route.h" #include "icmpv6/icmpv6.h" #ifdef CONFIG_NET_ICMPv6_NEIGHBOR /**************************************************************************** * Private Types ****************************************************************************/ /* This structure holds the state of the send operation until it can be * operated upon from the event handler. */ struct icmpv6_neighbor_s { FAR struct devif_callback_s *snd_cb; /* Reference to callback instance */ sem_t snd_sem; /* Used to wake up the waiting thread */ uint8_t snd_retries; /* Retry count */ volatile bool snd_sent; /* True: if request sent */ uint8_t snd_ifname[IFNAMSIZ]; /* Interface name */ net_ipv6addr_t snd_ipaddr; /* The IPv6 address to be queried */ }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: icmpv6_neighbor_eventhandler ****************************************************************************/ static uint16_t icmpv6_neighbor_eventhandler(FAR struct net_driver_s *dev, FAR void *priv, uint16_t flags) { FAR struct icmpv6_neighbor_s *state = (FAR struct icmpv6_neighbor_s *)priv; ninfo("flags: %04x sent: %d\n", flags, state->snd_sent); if (state) { /* Is this the device that we need to route this request? */ if (strncmp((FAR const char *)dev->d_ifname, (FAR const char *)state->snd_ifname, IFNAMSIZ) != 0) { /* No... pass on this one and wait for the device that we want */ return flags; } /* Check if the outgoing packet is available. It may have been claimed * by a send event handler serving a different thread -OR- if the * output buffer currently contains unprocessed incoming data. In * these cases we will just have to wait for the next polling cycle. */ if (dev->d_sndlen > 0 || (flags & ICMPv6_NEWDATA) != 0) { /* Another thread has beat us sending data or the buffer is busy, * Check for a timeout. If not timed out, wait for the next * polling cycle and check again. */ /* REVISIT: No timeout. Just wait for the next polling cycle */ return flags; } /* Prepare device buffer */ if (netdev_iob_prepare(dev, false, 0) != OK) { return flags; } /* It looks like we are good to send the data. * * Copy the packet data into the device packet buffer and send it. */ icmpv6_solicit(dev, state->snd_ipaddr); IFF_SET_IPv6(dev->d_flags); /* Don't allow any further call backs. */ state->snd_sent = true; state->snd_cb->flags = 0; state->snd_cb->priv = NULL; state->snd_cb->event = NULL; /* Wake up the waiting thread */ nxsem_post(&state->snd_sem); } return flags; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: icmpv6_neighbor * * Description: * The icmpv6_solicit() call may be to send an ICMPv6 Neighbor * Solicitation to resolve an IPv6 address. This function first checks if * the IPv6 address is already in the Neighbor Table. If so, then it * returns success immediately. * * If the requested IPv6 address in not in the Neighbor Table, then this * function will send the Neighbor Solicitation, delay, then check if the * IP address is now in the Neighbor able. It will repeat this sequence * until either (1) the IPv6 address mapping is now in the Neighbor table, * or (2) a configurable number of timeouts occur without receiving the * ICMPv6 Neighbor Advertisement. * * Input Parameters: * dev The suggested device driver structure to do the solicitation, * can be NULL for auto decision, must set for link-local ipaddr. * ipaddr The IPv6 address to be queried. * * Returned Value: * Zero (OK) is returned on success and the IP address mapping can now be * found in the Neighbor Table. On error a negated errno value is * returned: * * -ETIMEDOUT: The number or retry counts has been exceed. * -EHOSTUNREACH: Could not find a route to the host * * Assumptions: * This function is called from the normal tasking context. * ****************************************************************************/ int icmpv6_neighbor(FAR struct net_driver_s *dev, const net_ipv6addr_t ipaddr) { struct icmpv6_notify_s notify; struct icmpv6_neighbor_s state; net_ipv6addr_t lookup; int ret; /* First check if destination is a local broadcast or a multicast address. * * - IPv6 multicast addresses are have the high-order octet of the * addresses=0xff (ff00::/8.) */ if (net_ipv6addr_cmp(ipaddr, g_ipv6_unspecaddr) || net_is_addr_mcast(ipaddr)) { /* We don't need to send the Neighbor Solicitation. But for the case * of the Multicast address, a routing able entry will be required. */ return OK; } /* Get the device that can route this request */ if (!dev) { dev = netdev_findby_ripv6addr(g_ipv6_unspecaddr, ipaddr); } if (!dev) { nerr("ERROR: Unreachable: %08lx\n", (unsigned long)ipaddr); ret = -EHOSTUNREACH; goto errout; } /* Check if the destination address is on the local network. */ if (net_ipv6addr_maskcmp(ipaddr, dev->d_ipv6addr, dev->d_ipv6netmask) || net_is_addr_linklocal(ipaddr)) { /* Yes.. use the input address for the lookup */ net_ipv6addr_copy(lookup, ipaddr); } else { /* Destination address is not on the local network */ #ifdef CONFIG_NET_ROUTE /* We have a routing table.. find the correct router to use in * this case (or, as a fall-back, use the device's default router * address). We will use the router IP address instead of the * destination address when determining the MAC address. */ netdev_ipv6_router(dev, ipaddr, lookup); #else /* Use the device's default router IP address instead of the * destination address when determining the MAC address. */ net_ipv6addr_copy(lookup, dev->d_ipv6draddr); #endif } /* Allocate resources to receive a callback. This and the following * initialization is performed with the network lock because we don't * want anything to happen until we are ready. */ net_lock(); state.snd_cb = devif_callback_alloc((dev), &(dev)->d_conncb, &(dev)->d_conncb_tail); if (!state.snd_cb) { nerr("ERROR: Failed to allocate a callback\n"); ret = -ENOMEM; goto errout_with_lock; } nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */ state.snd_retries = 0; /* No retries yet */ net_ipv6addr_copy(state.snd_ipaddr, lookup); /* IP address to query */ /* Remember the routing device name */ strlcpy((FAR char *)state.snd_ifname, (FAR const char *)dev->d_ifname, IFNAMSIZ); /* Now loop, testing if the address mapping is in the Neighbor Table and * re-sending the Neighbor Solicitation if it is not. */ ret = -ETIMEDOUT; /* Assume a timeout failure */ while (state.snd_retries < CONFIG_ICMPv6_NEIGHBOR_MAXTRIES) { /* Check if the address mapping is present in the Neighbor Table. This * is only really meaningful on the first time through the loop. * * NOTE: If the Neighbor Table is large than this could be a * performance issue. */ if (neighbor_lookup(lookup, NULL) >= 0) { /* We have it! Break out with success */ ret = OK; break; } /* Set up the Neighbor Advertisement wait BEFORE we send the Neighbor * Solicitation. */ icmpv6_wait_setup(lookup, ¬ify); /* Arm/re-arm the callback */ state.snd_sent = false; state.snd_cb->flags = ICMPv6_POLL; state.snd_cb->priv = (FAR void *)&state; state.snd_cb->event = icmpv6_neighbor_eventhandler; /* Notify the device driver that new TX data is available. */ netdev_txnotify_dev(dev); /* Wait for the send to complete or an error to occur. * net_sem_wait will also terminate if a signal is received. */ do { net_sem_wait(&state.snd_sem); } while (!state.snd_sent); /* Now wait for response to the Neighbor Advertisement to be * received. */ ret = icmpv6_wait(¬ify, CONFIG_ICMPv6_NEIGHBOR_DELAYMSEC); /* icmpv6_wait will return OK if and only if the matching Neighbor * Advertisement is received. Otherwise, it will return -ETIMEDOUT. */ if (ret == OK) { break; } /* Increment the retry count */ state.snd_retries++; } nxsem_destroy(&state.snd_sem); devif_dev_callback_free(dev, state.snd_cb); errout_with_lock: net_unlock(); errout: return ret; } #endif /* CONFIG_NET_ICMPv6_NEIGHBOR */